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The trade-off between hardness and stretchability is a cornerstone of materials science. Balancing this trade-off is important in the molecular design of both chemical and physical networks. In this study, we report the quantitative trade-off at the molecular level for physical networks. Namely, we analyze, based on the reversible gelation model, a scaling relationship between the characteristic terminal relaxation modulus Gc in linear viscoelasticity and the stretch ratio λmax at the stress overshoot during the nonlinear elongation flow for unentangled randomly associative polymers, i.e., λmax ∼ Gc−0.17 and λmax ∼ Gc−0.33 in the mean-field and critical-percolation regimes, respectively. We use sulfonated polystyrene having different alkali counterions as a model system to test the relationship. The exponent of λmax ∼ Gc−0.25 seen in the experiment is in between the two theoretical values. We also discuss the quantitative deviation with respect to the size distribution of the network strands. [ABSTRACT FROM AUTHOR]

Anther-specific expression of OsRIP1 causes dominant male sterility in rice To clone I Dms1 i , we constructed a near-isogenic line (NIL) I -NJ4 i SP I Dms1 i sp contains the genetic background of the I japonica i rice variety I Ningjing4 i ( I NJ4 i ) but carries a chromosome segment insertion with I Dms1 i introduced from the mutant donor (Figure S1). When using the anther-specific I EAT1 i promoter to drive I OsRIP1 i in I Nip i , the male sterility phenotype mimicking NIL I -Nip i SP I Dms1 i sp appeared (Figure 1g). Keywords: rice; dominant male sterility; ribosome-inactivating protein; translation inhibition EN rice dominant male sterility ribosome-inactivating protein translation inhibition 1932 1934 3 09/20/23 20231001 NES 231001 Rice ( I Oryza sativa i L.) is a major staple food crop feeding more than half of the world human population. [Extracted from the article]

The ability to accurately predict the rheological behavior of the blends of two incompatible polymers is critical to the polymer industry. The constitutive modeling of incompatible polymer blends requires understanding the structure and dynamics of the blends across different length scales. The polydispersity of chain length at the molecular level and nonuniformity of flow field due to dispersed domains at the mesoscopic level present significant challenges to this industrially relevant problem. This work proposes a modeling framework for linear and nonlinear rheology of industrial incompatible polymer blends with sea-island morphology. For the individual components, we adopt the Rolie-Double-Poly model and generate the relaxation spectrum from an optimized molecular weight distribution. We derive a new mixing rule without empirical parameters from the flow field analysis inside and outside the droplets. The phase interface, modeled by an ellipsoidal model, contributes to the apparent rheology only at low shear rates. Our modeling approach is verified by the shear and extensional rheology of eight polymer blends with a broad range of viscosity ratios (0.01–100). We also show that the model has the ability to predict the nonlinear rheological behaviors of incompatible polymer blends with known molecular weight distributions and phase morphology. [ABSTRACT FROM AUTHOR]

Male sterility in plants provides valuable breeding tools in germplasm innovation and hybrid crop production. However, genetic resources for dominant genic male sterility, which hold great promise to facilitate breeding processes, are extremely rare in natural germplasm. Here we characterized the Sanming Dominant Genic Male Sterility in rice and identified the gene SDGMS using a map-based cloning approach. We found that spontaneous movement of a 1978-bp long terminal repeat (LTR) retrotransposon into the promoter region of the SDGMS gene activates its expression in anther tapetum, which causes abnormal programmed cell death of tapetal cells resulting in dominant male sterility. SDGMS encodes a ribosome inactivating protein showing N-glycosidase activity. The activation of SDGMS triggers transcription reprogramming of genes responsive to biotic stress leading to a hypersensitive response which causes sterility. The results demonstrate that an ectopic gene activation by transposon movement can give birth to a novel trait which enriches phenotypic diversity with practical utility. [ABSTRACT FROM AUTHOR]

Ride-hailing services provide an efficient way to travel, but they also cause some safety incidents, which make female passengers uneasy. Analyzing the safety perceptions of female passengers, particularly their psychological and emotional responses, can assist operators in developing effective solutions and safe travel environments for them. This study explores factors that are likely to affect the safety perception of female ride-hailing passengers using a subjective method (data was obtained from 596 Chinese female passengers). The methodologies adopted mainly include confirmatory factor analysis (CFA) and a maximum-likelihood structural equation model (ML-SEM). A passenger safety perception model is developed by considering various elements such as safety expectation, platform trust, perceived environment, and safety awareness. The results revealed that safety perception is positively influenced by perceived environment and safety expectation (containing three subdimensions, namely, driver behavior, traveling together, and mobile phone dependence). The effects of safety awareness and platform trust on safety perception are mediated by perceived environment and safety expectation, respectively. Regarding overall effects, safety expectation is the most powerful predictor for safety perception of female ride-hailing passengers, followed by platform trust, perceived environment, and safety awareness. Finally, countermeasures are offered from the perspectives of operators, drivers, and passengers to enhance the safety perception of female ride-hailing passengers. A high level of ride-hailing safety would undoubtedly boost the female passenger's trust and consequently ridership. [ABSTRACT FROM AUTHOR]